JP2000278014A - Antenna for radio unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna for radio unit that can freely be extracted from and housed in a housing of the radio unit and whose housing size can be short. SOLUTION: This antenna is provided with a bottom loading element 12 that projects externally from a radio unit enclosure and whose length is 1/8 wavelength with respect to a transmission reception frequency and with a moving element 12 whose length is 1/2 wavelength and freely extracted from and retracted to the radio unit enclosure coaxially. In an extended state, a base of the moving element 12 is electrically connected in series with a tip of the bottom loading element 10 and the entire antenna acts like an antenna whose length is 5/8 wavelength. In a contained state, the bottom loading element 10 and the moving element 12 are not electrically connected and only the bottom loading element 10 acts like an antenna whose length is 1/8 wavelength. Since the length of the moving element 12 is as short as 1/2 wavelength, the size for containing can be short, and then the size of the radio unit enclosure is made small. Moreover, the antenna input/output impedance is nearly the same between the extended state and the housed state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna which can be pulled out and housed in a housing of a radio equipment, and which has a short storage size and is sufficient.

[0002]

2. Description of the Related Art An example of a radio antenna generally used in a conventional portable telephone will be briefly described with reference to FIG. FIGS. 7A and 7B are structural diagrams of an example of a conventional antenna for a wireless device called a parallel operation system, in which FIG. 7A is a diagram showing a pulled-out state, and FIG. 7B is a diagram showing a housed state. FIG.
, A bottom loading element 10 formed of a helical coil antenna element protruding out of the radio device housing is fixedly disposed, and is formed of a whip antenna element so as to be able to be pulled out and stored in the radio device housing in the axial direction thereof. Movable element 12 is provided. Then, as shown in FIG. 3A, in the pulled-out state, the base end of the movable element 12 and the base end of the bottom loading element 10 are both electrically connected to the feeding unit 14, and the movable element 12 and the bottom loading element 10 are connected in parallel. Act as Further, as shown in (b), in the housed state, the movable element 12 is not electrically connected to the bottom loading element 10 and the power supply section 14,
Only the bottom loading element 10 is electrically connected to the power feeding portion 14 and the bottom loading element 10
Acts alone as an antenna. Here, an example of the effective antenna length of the bottom loading element 10 and the movable element 12 with respect to the transmission / reception frequency is set to 5/8 wavelength. Therefore, the antenna functions as a ／ wavelength antenna in both the pulled-out state and the housed state.

Another example of a radio antenna widely used in a conventional portable telephone will be briefly described with reference to FIG. FIGS. 8A and 8B are structural diagrams of another example of a conventional radio antenna called a separate system, in which FIG. 8A is a diagram showing a pulled-out state, and FIG. 8B is a diagram showing a housed state. 8, a top loading element 18 formed of a helical coil antenna element is provided coaxially and integrally at the tip of a movable element 12 with an insulating portion 16 interposed therebetween. The insulating portion 16 is formed so that the distal end of the movable element 12 and the proximal end of the top loading element 18 are not electrically connected in terms of direct current and capacitance. The movable element 12, to which the top loading element 18 is integrally fixed, is disposed so as to be freely drawn out and stored in the radio device housing. Then, as shown in (a), in the pulled-out state, the base end of the movable element 12 is electrically connected to the power supply unit 14, and the movable element 12 independently functions as an antenna. Also,
As shown in (b), in the housed state, the movable element 12 is not electrically connected to the power supply unit 14, but the top loading element 18 is protruded to the outside of the wireless device housing, and its base end is electrically connected to the power supply unit 14. Connected, and the top loading element 18 alone acts as an antenna. here,
With respect to the transmission / reception frequency, an example of the effective antenna length of the movable element 12 and the top loading element 18 is set to 5/8 wavelength. Therefore, the antenna functions as a ／ wavelength antenna in both the pulled-out state and the housed state.

[0004]

In the above-mentioned parallel-operation type radio antenna shown in FIG. 7, the movable element 12 must be 5/8 in order to operate as a 5 / 8-wavelength antenna in the extended state. The length of the wavelength is required, and the size of the radio housing for housing the movable element 12 is 5 /
It must be at least 8 wavelengths.

In the separate type radio antenna shown in FIG. 8, the movable element 12 needs to be 5/8 in order to operate as a 5/8 wavelength antenna in the pulled-out state as in the parallel operation type. The length of the wavelength is required, and the size of the radio housing for accommodating the movable element 12 must be 5/8 wavelength or more. Further, in the pulled-out state, the one having the size obtained by adding the movable element 12, the insulating portion 16, and the top loading element 18 is projected outward from the radio device housing, and the drawn-out size is long, and the drawer is damaged by the length. easy. Further, the movable element 12 and the top loading element 18
Is mechanically connected, and is formed of an insulating resin or the like, and is easily damaged.

By the way, a portable wireless device such as a mobile phone is desirably small and lightweight, and it is desired that the dimensions of the wireless device housing be as short as possible. Therefore, there is a strong demand that the antenna for a wireless device housed in the wireless device housing be required to be housed in the housed state and have a dimension as short as possible.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a radio antenna which is required to be stored in a stored state and can be reduced in size.

[0008]

In order to achieve the above object, an antenna for a radio device according to the present invention is provided with a bottom loading element that protrudes outward from a radio device housing, and a movable element is attached to the radio device housing. The bottom end of the bottom loading element is electrically connected to the base end of the movable element so that the bottom end of the movable element is electrically connected to the bottom end of the bottom loading element so that the bottom loading element and the movable element are electrically connected in the storage state. It is configured not to be connected.

[0009] With respect to the transmission / reception frequency, the impedance of the effective antenna length of the movable element and the bottom loading element connected in series in the extended state is the same as the impedance of the effective antenna length of the bottom loading element alone in the retracted state. May be configured.

The bottom loading element may be formed by a helical coil antenna element, and the movable element may be formed by a whip antenna element.

Further, the effective antenna length of the movable element is 波長 wavelength of the transmission / reception frequency, and the effective antenna length of the bottom loading element is ８, 1 /
The wavelength may be set to any one of 4, 3/8, and 1/2 wavelength.

Furthermore, the effective antenna length of the movable element is set to １ ／ wavelength of the transmission / reception frequency, and the effective antenna length of the bottom loading element is set to を, 1
The wavelength may be set to any one of ４, ／, and 波長 wavelength.

The bottom loading element may be formed by a folded antenna element, and the movable element may be formed by a whip antenna element.

[0014]

FIG. 1 shows a first embodiment of the present invention.
This will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of a first embodiment of a radio antenna according to the present invention in an extended state. FIG. 2 is a longitudinal sectional view of the first embodiment in a stored state. 3A and 3B are structural diagrams of the first embodiment, in which FIG. 3A is a diagram illustrating a pulled-out state, and FIG. 3B is a diagram illustrating a stored state.

In FIG. 1 and FIG. 2, a mounting metal 20 made of a conductive metal is fixed and electrically connected to a base end of a bottom loading element 10 made of a helical coil antenna element, and a distal end made of a conductive metal. Is fixed and electrically connected. Then, a storage tube 24 made of an insulating resin is inserted and disposed inside the bottom loading element 10 and the mounting bracket 20. Further, a support member 26 made of an insulating resin is provided outside the distal end portion of the mounting member 20 and the bottom loading element 10 and the holder member 22, and the mounting member 20 and the holder member 22 are fixed to each other. Is not changed. In the figure, a fixing structure by screwing is adopted, but the support member 26 may be integrally formed by insert molding or the like. Further, a base end side of the mounting bracket 20 is inserted and fixed to a radio device housing (not shown) by screwing or the like, and a power feeding portion 14 made of a conductive spring material is provided at a base end protruding into the radio device housing. The electrical connection is made by elastic contact. Needless to say, the power supply unit 14 is electrically connected to a radio circuit (not shown).

A movable element 12 composed of a whip antenna element is disposed inside the storage tube 24 so as to be freely retractable. A stopper 28 made of a conductive metal is fixed to and electrically connected to the base end of the movable element 12, and when the stopper 28 is pulled out, movement in the pulling-out direction is regulated to prevent the pull-out. A top 32 is provided at the distal end of the movable element 12 via a distal insulating section 30 made of an insulating resin or the like. The top 32 is a knob for pulling out and acts to restrict movement in the storage direction during storage. Further, a sleeve 34 made of a conductive metal is provided on the distal end side of the distal end insulating portion 30. Further, an insulating tube 36 made of insulating resin is covered on the intermediate portion of the movable element 12. The end of the storage tube 24 may be closed so that rainwater or the like, which may enter the storage tube 24, does not enter the housing of the wireless device. Alternatively, rainwater or the like that may enter the storage tube 24 may be discharged to the outside of the wireless device housing by appropriately opening the communication port.

The movable element 12 is elastically contacted with the stopper 28 when the movable element 12 is pulled out.
A contact spring 38 made of beryllium copper or the like having conductivity and elasticity is disposed in the holder 22 so as not to move in the axial direction so as to resiliently contact the holder.

In this configuration, when the antenna is pulled out, the base end of the movable element 12 is
8, the contact spring 38, and the holder 22 are electrically connected to the tip of the bottom loading element 10 in this order. Moreover, the bottom loading element 10
Is electrically connected to the power supply unit 14 via the mounting bracket 20. Therefore, the movable element 12 and the bottom loading element 10 are connected in series, and this series connection works as an antenna. In the stored state, the sleeve 34 is electrically connected to the tip of the bottom loading element 10 via the contact spring 38 and the holder 22. Here, the movable element 12 is provided with a tip insulating portion 30.
As a result, it is separated from the holder fitting 22 and the mounting fitting 20, and is not electrically connected to the holder fitting 22 and the mounting fitting 20 both in terms of direct current and capacity. Therefore, the bottom loading element 10 alone functions as an antenna. In practice, the bottom loading element 10
It is needless to say that the holder fitting 22 and the sleeve 34 electrically connected to the tip of the antenna also function as an antenna.
Therefore, the effective antenna length of the bottom loading element 10 is appropriately set in consideration of the length of the sleeve 34 projecting from the bottom loading element 10. And the bottom loading element 1 in appearance
The physical length of 0 can be shortened.

Therefore, the effective antenna length of the movable element 12 is １ ／ wavelength and the effective antenna length of the bottom loading element 10 is 1 wavelength with respect to the transmission / reception frequency.
If the wavelength is / 8, the antenna functions as a ５ wavelength antenna in the pulled-out state, and functions as a ８ wavelength antenna in the housed state. Here, the antenna input / output impedances of the antenna effective length of the ／ wavelength and １ ／ wavelength are almost the same. Therefore, even if a matching circuit is required, the same matching circuit can be used in the drawn state and the housed state. Moreover, as shown in FIG. 3A, if the effective length of the antenna is set to 5/8 wavelength in the pulled-out state, the movable element 12 of the present invention has 1/2 wavelength.
As shown in (b), in the stored state, the size required for the storage is shorter than that of the conventional one. Therefore, it is suitable for reducing the size of the wireless device housing that houses the wireless device.

FIG. 4 is a structural diagram of a second embodiment of the radio antenna of the present invention in which the effective antenna length of the bottom loading element is different from that of the first embodiment. In the second embodiment shown in FIG. 4, both the movable element 12 and the bottom loading element 10 are が.
Set to wavelength. With such a configuration, the antenna functions as an antenna having an effective wavelength of one wavelength in the pulled-out state, and functions as a half-wavelength antenna in the housed state. First
As in the embodiment, the storage dimensions are short enough, and the antenna input / output impedance is substantially the same between the pulled-out state and the stored state. In addition, in the pulled-out state, the negative-phase component is reduced and entered by the coil of the bottom loading element 10 despite having one wavelength, so that a radiation characteristic of approximately 1/2 wavelength can be obtained. Therefore, no null point of gain is generated in the horizontal direction, which is suitable for communication using a vertically polarized wave such as a mobile phone.

In the first and second embodiments, the effective antenna length of the bottom loading element 10 is not limited to the above embodiment, but is set to 設定, ／ wavelength or the like. Is also good.

FIG. 5 is a structural diagram of a third embodiment of the radio antenna of the present invention in which the effective lengths of the bottom loading element and the movable element are different from those of the first embodiment. In the third embodiment shown in FIG. 5, the movable element 12 is extremely shortened to 1/8 wavelength, and the bottom loading element 10 is set to 1/4 wavelength. With such a configuration, the antenna operates as an antenna having an effective length of 3/8 wavelength in the pulled-out state, and 1 / in the retracted state.
Acts as a four-wavelength antenna. And, compared with the first embodiment, the storage size is extremely short. Here, the input / output impedance of the antenna differs between the pulled-out state and the housed state. However, if a matching circuit of a wide band is appropriately used, the antenna can be practically used. Note that, in the third embodiment, the effective antenna length of the bottom loading element 10 is not limited to the above embodiment, and may be １ ／, ／, ２.
It may be configured to be set to any one of wavelengths and the like.

FIG. 6 shows a fourth example of the antenna for radio equipment according to the present invention.
FIG. 4 is a structural view of the embodiment in a drawn state. The fourth shown in FIG.
In the embodiment, a folded antenna element is used as the bottom loading element 40, and a whip antenna element is used as the movable element 12. The base end of the movable element 12 is electrically connected to the distal end of the bottom loading element 40 in the pulled-out state. An example of this folded antenna element is shown in Japanese Patent Application Laid-Open No. H11-68441. Briefly, the conductive pattern is folded back in the axial direction on a flexible substrate that is bent into a cylindrical shape, is disposed in a zigzag shape, and a base end of the conductive pattern as an element is provided at one end in the axial direction. The end of the conductive pattern as an element is provided at the end. Then, the flexible substrate is formed in a cylindrical shape, and the movable element 12 is pulled out and accommodated in the axial direction inside the flexible substrate to constitute a fourth embodiment of the present invention.

In the above embodiment, the movable element 1
Although a whip antenna element is used as 2,
The invention is not limited to this, and a helical coil antenna element having a small winding diameter may be used. Further, the bottom loading element 10 is not limited to a helical coil antenna element or a folded antenna element, and is configured such that the base end of the movable element 12 is electrically connected to the distal end of the bottom loading element 10 in a pulled-out state and connected in series. Then, any antenna element may be used for the bottom loading element 10. Furthermore, the effective antenna length in the pulled-out state and the stored state is not limited to
It may be an integral multiple of / 8 wavelength, and may be an integral multiple of 1/16 wavelength. In addition, the effective antenna length of the series-connected body depending on the pulled-out state is 3/8 wavelength or 1
If the wavelength is ２ wavelength, the current flowing to the ground in the wireless device casing is small, and even if a human body is brought close to the antenna, the influence is small. Therefore, it is particularly suitable as an antenna for a mobile phone used close to the human body.

[0025]

As described above, since the radio antenna of the present invention is constituted, the following special effects can be obtained.

According to the first aspect of the present invention, since the movable element and the bottom loading element are connected in series in the extended state, the effective antenna length of the movable element is equal to the effective antenna length of the series-connected body in the extended state. The dimensions required for storage are shorter in the stored state. Thus, the size of the wireless device housing that houses the wireless device can be reduced.

According to the second aspect of the present invention, the input / output impedance of the antenna is substantially the same between the pulled-out state and the housed state. Thus, matching can be achieved by connecting the same matching circuit, thereby simplifying the structure.

According to the third aspect of the present invention, since the helical coil antenna element and the whip antenna element are used, the configuration is simple.

In any of the radio antennas according to the fourth and fifth aspects, the effective antenna lengths of the bottom loading element and the movable element can be appropriately set, and the degree of freedom in design is large.

In the antenna for a wireless device according to the sixth aspect, since the folded antenna element is used as the bottom loading element, the bottom loading element is compared with the antenna using the helical coil antenna element formed of a wire or the like. Can be reduced in weight and is suitable for mass production.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a first embodiment of a wireless device antenna according to the present invention in an extended state.

FIG. 2 is a longitudinal sectional view of the first embodiment in a stored state.

FIGS. 3A and 3B are structural views of the first embodiment, in which FIG. 3A is a diagram illustrating a pulled-out state, and FIG. 3B is a diagram illustrating a housed state.

FIG. 4 is a structural diagram of a second embodiment in which the antenna effective length of the bottom loading element is different from that of the first embodiment in the radio antenna of the present invention.

FIG. 5 is a structural diagram of a third embodiment of the radio antenna of the present invention in which the effective antenna lengths of the bottom loading element and the movable element are different from those of the first embodiment.

FIG. 6 is a structural view of a fourth embodiment of the antenna for a wireless device of the present invention in an extended state.

FIGS. 7A and 7B are structural diagrams of an example of a conventional radio device antenna referred to as a parallel operation system, in which FIG. 7A is a diagram illustrating a pulled-out state, and FIG. 7B is a diagram illustrating a housed state.

8A and 8B are structural diagrams of another example of a conventional antenna for a wireless device called a separate system, in which FIG. 8A is a diagram showing a pulled-out state, and FIG. 8B is a diagram showing a housed state.

[Explanation of symbols]

 10, 40 Bottom loading element 12 Movable element 14 Power supply unit 20 Mounting bracket 22 Holder bracket 26 Support member 38 Contact spring

Claims (6)

[Claims] A bottom loading element is provided to protrude outward from a wireless device housing, and a movable element is provided in the wireless device housing so as to be retractable, and the movable element is attached to a tip of the bottom loading element in a drawn state. The base end is electrically connected and connected in series,
An antenna for a radio device, wherein the bottom loading element and the movable element are not electrically connected in the housed state. 2. The antenna for a radio device according to claim 1, wherein, with respect to a transmission / reception frequency, an impedance of an effective length of the movable element and the bottom loading element connected in series in a pulled-out state, and the bottom loading in a stowed state. An antenna for a wireless device, wherein the impedance of an effective antenna length of an element alone is configured to be the same. 3. The antenna for a radio device according to claim 1, wherein said bottom loading element is formed by a helical coil antenna element, and said movable element is formed by a whip antenna element. antenna. 4. The antenna according to claim 1, wherein the effective length of the movable element is 波長 wavelength of the transmission / reception frequency, and the effective length of the bottom loading element is ８, １ ／, or 、. 3/8, 1/2
An antenna for a wireless device, wherein the antenna is set to one of wavelengths. 5. The wireless device antenna according to claim 1, wherein an effective antenna length of the movable element is １ ／ wavelength of a transmission / reception frequency, and an effective antenna length of the bottom loading element is ８, １ ／, or 、. 3/8, 1/2
An antenna for a wireless device, wherein the antenna is set to one of wavelengths. 6. The radio antenna according to claim 1, wherein said bottom loading element is formed by a folded antenna element, and said movable element is formed by a whip antenna element. .